1. Field of the Invention
The present invention relates to an image processing. More particularly, the present invention relates to an automatic exposure control for sequential images.
2. Descriptions of the Related Art
Image capture and processing functions are widely implemented in consumer electronic devices, such as digital camera, smart phone or tablet. Images are generally captured by an input module comprising image sensors and lens. The raw images thus captured are performed with various processing before being provided for display and/or storage. Some processing may be general for all types of image capture operations, including photo shooting or video recording, for example de-noise that removes defect pixels. Some may be specific for desired functions/effects. For example, high dynamic range (HDR) is performed to produce images covering wider brightness range by combining two or more images captured by different exposure settings. However, surrounding light conditions may vary by background changes or time and thus cause the dynamic range of brightness of the scene to change, the exposure settings initially applied for capturing images may not be suitable at later time. Conventional exposure control for HDR images are performed by analyzing preview images prior to actual capture, but such technique is not applicable to real time image capture because it would cause significant delay between images. Therefore, there exists need for improved exposure control of image processing, particularly for sequential images in real time, such as video recording.